This disclosure is directed to a lamp assembly, and particularly to a method of fixing a first light source and a second light source in a single lamp assembly. More specifically, the invention provides a lamp assembly and a mechanism for fixing at least two light sources therein, at least one of which is a compact fluorescent light source, an incandescent light source, or a halogen light source.
Lamps have been introduced recently that address certain problems pertaining to run-up behavior of compact fluorescent lamps, i.e., reducing the time to full light associated with starting or igniting fluorescent lamps. By way of example only, long-life compact fluorescent lamps need approximately 0.5 to 1.5 seconds to preheat the cathodes or electrodes before starting. Before preheating is complete, there is no light emission from the lamp. Once the arc discharge is initiated, the CFL still requires an additional approximately 20 to 120 seconds or more to reach full light output.
One proposed solution combines two light sources in one unit or lamp assembly. More particularly, a compact fluorescent light source and a conventional incandescent or halogen light source are combined in a single lamp assembly. The term “hybrid CFL lamp” or “hybrid lamp” has been used to refer to such lamp assemblies. By way of example, this type of lamp may be configured such that an incandescent or halogen light source is positioned within the spiral or double-helix of a compact fluorescent light source. An advantage gained by such arrangement is the immediate light generated by the incandescent or halogen light source, providing instantaneous light emission, while the CFL lamp simultaneously undergoes its warm-up period, which may last from 0.5 to 120 seconds. An added benefit of this hybrid lamp configuration is the use of heat generated by the incandescent or halogen light source, which is centrally positioned within the configuration of the CFL discharge tube, to heat the discharge tube of the CFL more efficiently, i.e. the mercury dose is more quickly vaporized by the additional heat.
While the foregoing lamp configuration addresses concerns regarding reduced light emission during lamp warm-up, it nonetheless has experienced a disadvantage or drawback with regard to the method and manner of fixing two different light sources within a single lamp assembly. Problems are encountered due to the difference in operating temperature of the two different light sources, and the affect of the heat of operation on the components of the light sources. For example, because a conventional CFL lamp does not generate as high operating temperatures as an incandescent or halogen lamp, it is generally manufactured to include a plastic collar in that portion of the lamp where the light source joins the power source. The plastic conventionally employed has a lower rated heat tolerance, suitable for use with CFL lamps that generate less heat. The hybrid lamp design, however, pairs the lower operating temperature CFL with a higher operating temperature incandescent or halogen lamp, thus rendering the lower temperature rated plastic collar susceptible to degradation caused by exposure to such high heat. Even in those lamps of the hybrid design that include a mechanism to control the higher temperature light source once the CFL lamp is sufficiently energized, such as a thermal sensor or switching mechanism for example, the heat generated by the instantaneous light source still deleteriously affects the plastic collar of the CFL lamp.
Attempts have been made to address this problem. For example, one means of controlling the heat generated by the instant start-up lamp in the hybrid configuration is to leave the lamp bare, i.e. not to use a lamp envelope or bulb to enclose the two light sources. This however is not as aesthetically pleasing as a lamp including an envelope or bulb, and a certain amount of the heat that is dissipated away from the instant start-up lamp in this type of bare arrangement that could be used to heat the CFL discharge tube is lost.
Other attempts to address the issues created by high temperature heat transfer to a low temperature rated plastic collar include the use of heat insulator structures, such as ceramics, cement, glue, and other materials that will fix the fixtures in the desired configuration and absorb some of the heat generated during the initial start-up of operation. These measures, however, can prove costly, and are cumbersome during lamp manufacture.
There remains a need, therefore, for a method suitable for use with hybrid lamp designs for fixing two different types of light sources within a single lamp assembly, as well as for reducing degradation of low temperature rated lamp components caused by exposure to high operating temperatures of another light source housed within the same lamp assembly.